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Bring-up issue with iMX6Q ref. IMX6Q5EYM12AC

Question asked by Michaël Burtin on Nov 27, 2015

Hi,

 

We're currently bringing-up two prototypes with nearly same hardware. PCB is the same and all the parts are identical except the CPU.

One board have a IMX6Q6AVT10AC, and the other one IMX6Q5EYM12AC (which support 1.2GHz).

The latter have issue with DDR which is unstable. After much investigation, we can't didn't find any explanation for this failure.

The other board is working well.

 

So we wonder if there is some specific considerations with IMX6Q5EYM12AC processor, despite we didn't find any specific notes in datasheet ?

 

We did not find much information about specific 1.2GHz IMX6 processor so we assumed there's no differences except max frequency, is that correct ?

Any hint would be appreciated.

 

In attachment the calibration log.

What has been tested so far:

- increasing RALAT/WALAT

- changing DSE in I.MX6DQSDL DDR3 Script Aid,

- changing DDR frequency for calibration

- changing CPU frequency for calibration

- doing stress test using working board calibration

- HW Design checklist

- bus length check with HW Design checklist

(And probably more that I forget)

 

I saw in another thread someone advising "try using different drive strength for DRAM signals for both  i.MX6 and DRAM part", what DSE is he referring to when saying for iMX6 part ?

 

 

Regards,

Michaël

Original Attachment has been moved to: calibration_log_jtag.txt.zip

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